The candidate's long-term career objective is to investigate biomechanical factors contributing to musculoskeletal dysfunction, in order to refine current clinical treatment approaches and develop novel scientifically founded rehabilitation interventions. A five-year research and training plan developed with the primary mentor and a team of experienced scientists will expand the candidate's scientific background in biomechanics and musculoskeletal modeling, enrich her direct research skills and experience in the scientific process, promote integration of research findings to clinical practice, and advance skills necessary for becoming an independent investigator. The long-term objective of the research plan is to develop and test the effectiveness of biomechanically based rehabilitation strategies for improving upper extremity function and reducing pain and disability in persons with shoulder pathologies related to abnormal shoulder movement patterns. In-vivo 3-D full shoulder complex kinematics (thorax, clavicle, scapula, and humerus) during arm elevation will be collected from healthy and symptomatic subjects and integrated with a state of the art shoulder model to describe the 3-D muscle function of selected shoulder muscles, allowing comparisons among muscles for their relative biomechanical ability to reduce shoulder kinematic deviations, or contribute to deviations if producing excess or inadequate force (Aim 1). Computerized Tomography scans of the shoulder complex structures will be taken and imaging data combined with the kinematic data, allowing determination of the effects of abnormal kinematics on the available volume of the subacromial space, providing insight into how specific kinematic deviations create impingement of soft tissue structures (Aim 2). Determining and demonstrating muscle activations that can improve scapular kinematics and reduce subacromial impingement can provide a template for scientifically based intervention approaches that can be further tested through clinical trials.